Warm air furnace

The invention discloses a warm air furnace, which comprises a furnace body, wherein the furnace body is provided with a stove port, a flue, a hearth and a steam combustion-supporting device; a flue heat absorbing pipe is arranged in the flue; the steam combustion-supporting device comprises a heating pipe, a steam bag, a water tank and a steam spray pipe; the water tank is arranged outside the furnace body and is communicated with the heating pipe through a water inlet pipe; the steam bag is communicated with a steam guide pipe in the water tank through a steam pipe; the steam pipe is communicated with a bypass pipe; the bypass pipe is positioned outside the furnace body and is communicated with the steam spray pipe through a connecting pipe nut; the steam spray pipe extends into the hearth through an outer wall of the furnace body; a positioning shaft is arranged in the flue; a positioning sleeve is sleeved outside the positioning sleeve; a scraping plate is sleeved outside the flue heat absorbing pipe; the positioning sleeve is fixedly connected with the scraping plate through a connecting rod; the positioning sleeve is provided with an operating handle; and the operating handle is positioned at the edge of the stove port. According to the warm air furnace, the time and labor for disassembling and assembling the steam spray pipe are saved, and the operation is convenient; and the defects brought by the fact that the operating handle is positioned on the left side or the right side of the furnace body can also be avoided.